Gelatin dynamite composition



lid

till) Patented June 19, 1934 Ul sr P OFFICE GELATIN DYNAMITE COMPOSITIONNo Drawing. Application May 19, 1932,

l Serial No, 612,384

10 Claims.

This invention relates, in general, to gelatin dynamltes having improvedexplosive properties and, more particularly, to gelatin dynamites whichexhibit superior sensitiveness and propagating ability after long,periods of storage and with nitroglycerin, nitroglycol, and the like,or-

with mixtures of such nitrated aliphatic alcohols with nitrated aromatichydrocarbons such as trinitrotolueneor dinitrotoluene, in suchproportions as to produce a viscous, plastic, and cohesive mass.Explosive properties such as strength and gaseous products of combustionare modified and adjusted by addition of suitable oxidizing agents andcarbonaceous combustibles to the above-mentioned plastic mass.

The usual commercial gelatin dynamites vary in grade strength from 20%to depending on the explosive content. These grades also vary indensity, for example, from 1.70 for the low grades to as low as 1.50 forthe high grades.

The sensitiveness, or propagating power, of gelatin dynamites variesnotably depending on the composition and grade, but also to a markeddegree on the density of the explosive; the higher the density, thelower the propagating power, other things being equal. The propagatingpower of gelatin dynamites decreases with age because of a gradualincrease in density, this increase being due to loss of small airbubbles entrapped in the gelatins at the time of manufacture.Furthermore, in deep oil wells and in submarine blasting, where theexplosive is subjected to considerable external pressure, the density ofthe gelatin explosive is increased and its propagating power materiallydecreased.

It is quite common in the case of relatively deep submarine blasting forthe gelatin to be so adversely afiected by the water pressure that itfails to propagate completely, or that a portion of the charge burns,thereby failing to properly blast the rock, thus making it necessary tore-shoot after the dredge has cleaned up the area blasted.

This invention has as an object the production of gelatin dynamiteshaving substantially lower initial densities than have heretofore beenpracticable. A further object is the production of gelatin dynamiteswhich will maintain 10w densities and satisfactory sensitiveness andpropagating power, over long periods of time, under either atmosphericor greater than atmospheric pressures, and dynamites which are superiorto gelatins heretofore manufactured for use in oil or gas wells, and ingeneral submarine blasting. Other objects will present themselves as theinvention is more fully described hereinafter.

We have found that expanded, and in particular flaked, cereal grains areexceptionally capable of lowering the density of gelatin dynamites. Mostlow density carbonaceous materials such as wood pulp, vegetable fibres,and the like are highly absorbent, and if an attempt is made to userelatively high percentages of such materials in order to lower thedensity, the resulting explosives are dry and lacking in plasticity.Them qualities greatly interfere with the cartridging of the gelatinwith existing types of machines and impart undesirable physicalproperties to the explosives. Furthermore the lack of plasticity of suchgelatin works against obtaining low density because of the excessivepressure necessary in. order to extrude the gelatin into cartridge form.

We have found that, apparently, because of relatively low absorptionvalue and lack of fibrous character, expanded cereal products can beused to lower the density without adversely afiectlng the plasticity andthat higher percentages of such materials can be used than is true ofthe absorbents now used and yet obtain explosives which are well suitedfor cartridging on the existing types of machines.

For example, our low density, expanded cereal product may be poppedcorn, prepared by the 1 application of heat to any of the severalvarieties of maize commonly known as pop-corn (Zea everta) For thepurposes of our invention, it is desirable to reduce the size of thepopped kernels and this may be accomplished by any suitable 5- method ofgrinding. While the ground popped corn, as used, may be of any desireddegree of fineness, we prefer to use material the major portion of whichpasses a S-mesh screen and is re tained on a SO-mesh screen. All of themateused with satisfaction or, if so desired, the unpopped or partiallypopped kernels appearing with the product of ordinary poppingoperations, and the high density material comprising the hull of thecorn, may be separated and discarded, in which case a superior productof extremely low density is obtained. The ground popped corn may be usedwith the normal proportion of moisture remaining after popping or, as issometimes desirable, may be further dried.

Another means of obtaining our expanded cereal products consists in theprocess commonly known as pufing, whereby the cereal grains aresubjected to high external and internal pressures, with the subsequentsudden release of said pressures. We have found that various grainswhich lend themselves to the above treatment will accomplish ourpurpose, such as, for example, wheat, rice, etc. In such treatment, thepressure applied from without (usually steam) permeates the material ofthe grain and, when the external pressure is released, the pressurewithin the grain walls causes the explosion or pumng of the grainkernel, thus resulting in a light, fluffy material. Inasmuch as thepufied grains resulting from this treatment remain substantially intact,our purposes are best suited by grinding or crushing the material so asto make it more readily combustible in explosive compositions. Weprefer, however, to cut the material to obtain the proper form, in ordernot to destroy the low density properties existing in the originalpuffed grain. What has been said previously in regard to the preferredfineness and moisture contents of ground popped corn applies equally inthe case of the puffed grains.

In addition to the above, there exist several methods whereby cerealsand cereal products such as corn, wheat, rye, rice, starch, hominygrits, and like materials may be converted into the form of low densityflakes. The one most commonly used, which will be described in detailhereinafter, is known as the dry process of milling,- as distinguishedfrom the preparation of .starch, which involves what is known as the wetproces.

In the'dry process of milling, as applied generally to maize, the hullsand germs are removed and the grains broken into pieces, cooked by steamor other suitable means, and pressed to form flakes. by first temperingthe grains; which consists in softening them by means of a small amountof water, this treatmentrequiring usually from 3 to 4 hours. At the endof the soaking period, live steam is injected into the material. Theproduct is then passed to a degerminator, which breaks up the grain,releasing the germ, the hull, and the softer portion of the'starch whichsurrounds the germ. In this degerminating process, the horny portion ofthe maize kernel is usually .cracked or broken into several pieces. Itis this horny portion that is most suitable for producing low densityflakes. Other starchy portions, of course, may be flaked by themselvesor in combination with the horny portion properly reduced to uniformsize. The germ of the cereal grain contains a substantial amount of oil,and for this reason, it is desirable to remove this from the hornymaterial before flaking.

The resulting material, which at this point may be termed crude hominy,is then subjected to a cooking process which is intended primarily toslightly soften and preheat the grain before This dry process isaccomplishedrial obtained by popping and grinding may be entering thenext step in the process. In this cooking process, the temperature ofthe crude hominy is usually raised to approximately 200 to 250 F. Thehot, moist material is then subjected to high pressure, for example bypassing through heavy rolls. relatively high temperature and the thustreated grains, in passing through the rolls, are converted into a stificohesive flake or sheet.

If the product from the hot rolls is in the form of flakes or sheets,then, in order to convert these flakes or sheets into proper form forour purpose, it is necessary to subject themto a rough grinding processin order to reduce the flakes or sheets to smaller particles suitablefor mixing with other explosive ingredients. Flakes of a size suitablefor direct use in explosives can be produced, provided the grainparticles known as grits are sufficiently small in size. We have foundthat a suitable materiai is of such a size that a major portion willpass a 6-mesh screen and at the same time be held on a (SO-mesh screen.

There are many variations in the process described in the foregoing;both in the preliminary preparation of the grain and in the handling ofthe material from the rolls. The essential features of the process,however, lie in passing a treated cereal or cereal product through hotrolls in order to convert it into flakes. There are other processes forproducing flaked cereal products. For example, another type of processcomprises delivering the moist cereal product to a hot roll providedwith a scraper, where the product is dried and gelatinized and removedfrom the drum by the scraper. Such processes are well known in the art.

While we have found that all materials resulting from the processessdescribedin the foregoing are substantially lower in density thansimilar untreated materials, we prefer to use those having These rollsoperate at a liiii a density less than 0.3, preferably between 0.1 andOur invention is applicable to all types of gelatinous dynamites andsemi-gelatinous amites. The three main classes of the gelatin dynamitesare commonly known as straight gelatins, am-

monia gelatins, and permissible gelatins. The straight gelatins range instrength, accordingrto the usual terminology, from 20% to 100%. The

latter is commonly known as blasting gelatin.

The ammonia gelatins usually contain be of either the straight or theammonia. type,

with the addition of a safety ingredient which permits their safe use incoal mines, where there is danger of explosion from mine gas and coal Idust. The semi-gelatins usually contain a relatively small proportion ofgelatinized liquid explosive ingredient and a relatively largeproportion of ammonium nitrate, and their densities are generallysubstantially lower than those of either the straight or ammoniagelatins.

Semigelatins containing no ammonium nitrate, and

having a relatively high density, are also in some use and, while noexample of thistype will be given, it is to be understood that suchcompositions also fall within the scope of our invention.

While our invention is applicable to many different forms StraightAmmonia Permis- Semi- Type gelatin ingredient sible gelatinNitroglyeerin 4'1. 0 e0. 0 so. a 22. o Dinitrotoluene- 3. 0 3. 5 2. 0 1.5 Nitrocotton- 1. 3 2. 3 0. 7 0. 2 Sodium mtrate- 36. 1 2. 2 44. 8 9. 0Ammonium nitrate 24. 0 60. O Ammonium chloride. l5. 0 Expanded cerealproduct. 9. 0 6. 0 2. 0 6. 9 Starch 2. 7 l. 0 4. 5 Chalk 0. 9 l. 0 1. 00. 4

As further illustrative of the value of our invention, we show below acomparison of the formulas and properties of a standard 60% straightgelatin (A) and those of representative 60% straight gelatins (B and C),containing one of our low density cereal products.

A B C Nitroglyoerin 47. 0 47. 0 47. 0 Dinitrotoluene 3. 0 3. 0 3. 0Nitrocotton 1. 3 1. 3 1. 3 Sodium nitrate 41. 7 36. l 36. 1 Wood pulp(density 0.22) 6. 1 Flaked maize product (density 0.10) (7) g: 2 Calciumcarbonate 0. 9 0. 9 0. 9 Density after 1 days storage l. 65 l. 52 1. 47Sensitivenesu after 1 day's storage--. 12 20 20' Velocity, meters/sec.alter 1 week of mmersion in water at 15 lbs./sq.

.and 10% of these materials as most satisfactory.

It will be understood, of course, that the percentage of ingredientsgiven in the foregoing examples may be varied within wide limits, andthat additional ingredients may be introduced without departure from thespirit of our invention. It is also to be understood that we do notlimit ourselves to the use of expanded cereal products as the solecombustible material, either high or low density, inasmuch as certainproperties of other combustibles may cause their use to be of advantage.We may also use in place of all or part of the nitroglycerin, forexample, nitroglycol, nitrated polymerized glycerin, nitrated sugars,nitrated aromatic hydrocarbons, and like compounds.

It is to be understood that we intend to be limited in our inventiononly as indicated in the following patent claims.

We claim:

1. An explosive composition comprising a gelatinized liquid explosureand an expanded cereal product.

2. An explosive composition comprising a gelatinized liquid explosiveand ground popped corn.

3. An explosive composition comprising a gelatinized liquid explosiveand a disintegrated puffed cereal grain.

4. An explosive composition comprising a gelatinized liquid explosiveand a flaked cereal product.

5. An explosive composition comprising as ingredients a gelatinizedliquid explosive and an expanded cereal product, which, when ground topass a 6-mesh screen, has a density not greater than 0.3.

6. A gelatinous explosive comprising a liquid explosive ingredient,nitrocellulose, and from 0.5 to 15.0% of an expanded cereal product.

7. A gelatinous explosive, characterized by its relatively low density,comprising nitroglycerin, nitrocotton, and from 0.5 to 15.0% of a flakedcereal product.

8. A gelatine dynamite, characterized by its relatively low density,containing as ingredients nitroglycerin, nitrocotton, and a flaked maizeproduct, from which the germ and hull portions have been removed, saidflaked product having a densitybetween 0.1 and 0.2.

9. A gelatinous explosive, characterized by its relatively low density,containing as ingredients nitroglycerin, nitrocotton, one or moreinorganic oxidizing materials, carbonaceous combustible materials, and aflaked maize product, in the amount of 0.5 to 15.0.

10. An explosive composition comprising a gelatinized liquid explosiveand cereal grains having an artificial gelatinized dry outer layer,resistant to theescape of fluid under pressure from the interior of thegrain.

NORMAN G. JOHNSON. CLIFFORD A. WOODBURY.

